Packers are used for zone isolation downhole. They are available in a variety of designs and are integrated into a tubular string for proper positioning in a wellbore. Some are set with pressure and others with applied force from the tubular string to which they are attached. More recently packers have been developed that swell in the presence of fluids in or added to the wellbore. Some of these packers swell in the presence of water and others in the presence of hydrocarbons. Such packers can be used on casing or tubular strings running through casing.
These swelling packers are prefabricated into a pup joint that can be made part of a longer string. Generally the swelling element is wrapped around the pup joint, bonded and cured directly to the outer wall of the pup joint. Other designs have used a swelling material on a cylindrical housing that is slipped over the casing or tubing. However, such designs are a set length and do not provide a means of joining additional segments to make the packer longer or combine both water and oil swell elastomers in a single packer assembly. Also the rigid housing can cause problems running in the hole and can make sealing between the housing and the tubular difficult. In essence, they act as a barrier in the annulus but not as a pressure seal between wellbore sections. Clamp on pipe protectors which attach to drill pipe are used to protect the casing from wear caused by rotating and reciprocating the drill pipe. An example of such clamp type pipe protector is U.S. Pat. No. 4,266,578.
The present invention provides a swelling seal that has a split to allow encircling the tubular and securing it to the tubular. It is a modular design that can use an interlocking feature among sealing modules. Multiple element modules can be joined together to make a packer assembly as long as desired using all oil swell, all water swell, or a combination of oil and water swell elements. End rings can serve to protect the assembly during run in and to act as extrusion barriers once the packer is in position and the elements are swollen. The modules can have an embedded body that closes around a tubular with offset tapered loops that can be drawn together with a tapered pin that is driven into position to tighten the element onto the tubular. Excess length of the tapered pin is trimmed off to allow additional elements to be added which interlock with the previously installed element. The pins and the joints they close are circumferentially offset to prevent straight through leak paths among modules. The split design also allows these packer assemblies to be installed on tubulars other than casing such as sand screens, drill pipe, or other tools with a round profile. These and other features of the present invention will be more readily understood by those skilled in the art from a review of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the claims appended below.